Field
This disclosure relates generally to circuits, and more specifically, to a charge pump circuit that provides a multiplied voltage.
Related Art
For integrated circuits manufactured at advanced semiconductor processing nodes such as 28 nm (nanometer) feature size and smaller, leakage current between the source and drain terminals of transistors is an increasing problem, especially in very large integrated circuits having a large number of transistors. Metal oxide semiconductor (MOS) transistors are typically characterized as being four terminal devices having a gate, drain, source, and body terminals. One way to reduce leakage current in a MOS transistor is to independently bias the body terminals of the transistors with a reverse body bias instead of coupling the substrate terminals to the corresponding power supply terminals. A charge pump is generally used to generate the independent bias voltage. However, the charge pump can have very poor efficiency and limited voltage range being greatly impacted by the body effect of the pump transistors. As such, there is a need to not only improve the efficiency of the charge pump, but also to extend the voltage range of the charge pump.